ISLAMABAD: Assailants in Pakistan launched two separate attacks Friday on vehicles carrying fuel for NATO and American forces in Afghanistan, highlighting the vulnerability of the US-led mission a day after Pakistan closed a major border crossing. A truck driver and his assistant were burned alive in the second attack on a single tanker in the parking lot of a restaurant in southeastern Baluchistan province, said police officer Mohammad Azam. He said “anti-state elements” were behind the attack. Earlier Friday, suspected militants torched 27 tankers carrying oil for troops in Afghanistan in Sindh province. The Pakistani government shut the Torkham border crossing in the northwest on Thursday in apparent protest of a NATO helicopter incursion that killed three of its soldiers on the border. It kept open the Chaman crossing in Balochistan, where it seemed likely the vehicles attacked Friday were heading. The closure raised tensions between Pakistan and the United States, which have a close but often troubled alliance in the fight against militants. In Sindh, around 10 gunmen attacked the tankers when they were parked at an ordinary truck stop on the edge of Shikarpur town shortly after midnight. They forced the drivers and other people there to flee before setting the fires, said police officer Abdul Hamid Khoso. Another officer, Nisar Ahmed, said the tankers had arrived in Shikarpur from Karachi and were heading to Quetta, a major city in the southwest. From there, the road leads to Chaman. Attacks on NATO and US supply convoys in Pakistan give militants a propaganda victory, but coalition officials say they do not result in shortages in Afghanistan. Some of the attacks are believed to be the work of criminals or in Balochistan, separatists. Some officials allege truck owners may be behind some of them, perhaps to fraudulently claim insurance. On Thursday, three Pakistani soldiers were killed and three wounded in two cross-border incursions by NATO forces chasing militants in Pakistan's northwestern Kurram region. It was the third cross-border incident in a week, the Pakistan military said. NATO said the helicopters briefly crossed into Pakistan airspace after coming under fire from people there. Pakistan's Prime Minister Yousaf Raza Gilani, speaking in Parliament, said Pakistan was a partner in the war against militancy, but would allow no infringement of its sovereignty. “I want to assure the entire nation from this house that we will consider other options if there is interference in the sovereignty of our country,” Gilani said without elaborating. In Brussels on Friday, Pakistani Ambassador Jalil Abbas Jilani met with NATO leaders and lodged a formal protest over the border incursions. In Pakistan, government officials said they had to take a stand. – Agencies “If the NATO forces keep on entering into Pakistan and carrying out attacks, then (the) only option we have – we should stop the movement of the containers,” Defense Minister Chaudhry Ahmed Mukhtar said. __